This essay describes the general pattern by which modern nation-states have formed, largely from empires, in the modern world since 1800. There were three major waves of formation, each triggered by somewhat different circumstances.
In 1800 there were fifteen states in the world that have continued to exist. These comprised, Great Britain, France, Spain, Portugal, Denmark, Sweden, Switzerland, and Russia in Europe; Iran (Persia) in the Middle East; Afghanistan, China, Japan, Nepal, and Thialand in Asia; and Ethiopia in Africa; Some of these were, of course, the hegemonic states within empires. From 1800 to 1900, 29 more independent states were formed, and from 1900 to the present another 146 have formed. There were also several empires: the British, French, Spanish, Portuguese, Swedish, Russian, and Ottoman.
In the nineteenth century, eight more independent nations were formed in Europe: the Benelux countries (1830); Italy and Germany by unification; and three others hiving off from the Ottoman Empire. Belgium, Italy, and Germany then undertook their own imperialistic expansions. In the Americas, the USA had assumed its modern form by 1789; Haiti attained independence from France in 1804, Brazil (from the Portuguese) in 1822, and Canada in 1867; 16 more countries broke free from the Spanish Empire between 1810 and 1844. In the Middle East, Asia, and Oceania, no independent nations were formed in the nineteeth century, and in Africa only Liberia was formed.
In the twentieth century, matters naturally became more complicated. In Europe and the Middle East, many states were formed after the end of World War I from the breakup of the Austrian-Hungarian, Russian, and Ottoman Empires; these included Albania (1912), Yugoslavia, Austria, Hungary, the Czech Republic, Poland (which had been partitioned among the Austrian, Russian, and German Empires), Finland, and Turkey. Saudi Arabia had become independent in 1902, and Yemen, ...